LNimoy
Member
Good morning,
Three weeks ago, I took my 66, 289 4v, out and had some issues with the trans shifting. It usually shifted nice and soft at 15 mph into second, and then softly again into third at 30 mph or so. This time it wouldn't shift into 2nd until 30 mph, and shifted hard, and I didn't think it ever shifted into 3rd. I ordered a new vacuum modulator and installed it last week. Same problem existed. I went to adjust the module and found that the adjustment screw had almost backed out completely. I can easily spin it in and out, checked the old modulator, and the screw seems to have a bit of tension on it when adjusting it. Ordered another modulator which arrived this week. I'll be installing it today.
I spent a few hours searching here and the other site looking for similar issues. After lots of reading, I did the following yesterday. Everything done at operating temp.
Adjusted the carb with a vacuum gauge to get the best vacuum reading. Advanced the timing to 10 degrees, retuned the carb. I have increased the vacuum reading from 15 to 16.5.
I checked the vacuum at the manifold and down at the modulator and it's 16.5 at both places. I replaced the rubber hose at the modulator.
The trans fluid is full and cherry red. The tranny was completely rebuilt 22 years ago when I restored the car. I have about 12,000 miles on it since. It does sit for months at a time during the winter.
The modulator did not have any fluid running through it and when I push on the pin, I feel the spring pushing back.
I purchased and installed a tach to see if I could tell if it was shifting into 3rd. I brought it up to 65 mph. I could see the rpms drop on the 1-2 shift, but it never dropped down again so I assume there is no 2-3 shift. I was doing 60 mph at 2600 rpms. Floored it and brought it up to 4500 rpms and still no shift.
I checked the vacuum at 1000 rpms, 18.5, at 2000, 3000, and 4000 rpms it was at 21. If I go to WOT and let off, it goes off the scale,25, down to 0, and then settles back in at 16.5.
Does this sound right? Can my throttle valve be sticking?
I'll be putting in some lube guard and a new modulator this afternoon. Just asking here what I may be missing if the 3rd modulator exhibits the same issues.
Thanks
Three weeks ago, I took my 66, 289 4v, out and had some issues with the trans shifting. It usually shifted nice and soft at 15 mph into second, and then softly again into third at 30 mph or so. This time it wouldn't shift into 2nd until 30 mph, and shifted hard, and I didn't think it ever shifted into 3rd. I ordered a new vacuum modulator and installed it last week. Same problem existed. I went to adjust the module and found that the adjustment screw had almost backed out completely. I can easily spin it in and out, checked the old modulator, and the screw seems to have a bit of tension on it when adjusting it. Ordered another modulator which arrived this week. I'll be installing it today.
I spent a few hours searching here and the other site looking for similar issues. After lots of reading, I did the following yesterday. Everything done at operating temp.
Adjusted the carb with a vacuum gauge to get the best vacuum reading. Advanced the timing to 10 degrees, retuned the carb. I have increased the vacuum reading from 15 to 16.5.
I checked the vacuum at the manifold and down at the modulator and it's 16.5 at both places. I replaced the rubber hose at the modulator.
The trans fluid is full and cherry red. The tranny was completely rebuilt 22 years ago when I restored the car. I have about 12,000 miles on it since. It does sit for months at a time during the winter.
The modulator did not have any fluid running through it and when I push on the pin, I feel the spring pushing back.
I purchased and installed a tach to see if I could tell if it was shifting into 3rd. I brought it up to 65 mph. I could see the rpms drop on the 1-2 shift, but it never dropped down again so I assume there is no 2-3 shift. I was doing 60 mph at 2600 rpms. Floored it and brought it up to 4500 rpms and still no shift.
I checked the vacuum at 1000 rpms, 18.5, at 2000, 3000, and 4000 rpms it was at 21. If I go to WOT and let off, it goes off the scale,25, down to 0, and then settles back in at 16.5.
Does this sound right? Can my throttle valve be sticking?
I'll be putting in some lube guard and a new modulator this afternoon. Just asking here what I may be missing if the 3rd modulator exhibits the same issues.
Thanks
